Combine porcini and boiling water in a small bowl, cover with a plate and set aside for 20 minutes.

Meanwhile, heat 1 tablespoon oil in a large pot over medium-high heat. Add fresh mushrooms, sprinkle with pepper, and cook without stirring for 2 minutes. Stir and continue to cook, stirring once or twice, until the mushrooms have given off their liquid and are well browned, about 4 minutes more. Add sherry (or vermouth) and cook, stirring, for 1 minute.

Add the remaining 2 teaspoons oil to the pot. Add onion, celery, carrot and bell pepper and cook, stirring frequently, until the onion is tender and translucent, about 4 minutes.

Meanwhile, line a sieve with a paper towel, place over a bowl and strain the porcini; reserve the liquid. Chop the porcini and add to the pot along with the strained liquid (discard the grit and dregs). Add broth, tomatoes, quinoa, marjoram (or oregano) and bay leaf; bring to a boil. Reduce heat to a simmer, cover, and cook for 20 minutes. Remove from heat, stir in soy sauce and season with pepper.